Sensor accommodated in a housing

Abstract

A sensor is described for measuring the parameters of a fluid, in particular for detecting substances in a gas. It comprises a measuring section ( 4 ) on a semiconductor chip ( 1 ), which is protected by a housing ( 3 ). A partition wall ( 12 ) of the housing ( 3 ) divides the semiconductor chip ( 1 ) into two parts ( 1 a , 1 b ). The first part ( 1 a ) is connected to the outside by means of openings in the housing and carries the measuring section. The second part ( 1 b ) is covered by a hardened sealing material ( 11 ). The sealing material ( 11 ) protects the semiconductor chip ( 1 ) from undesired environmental influences. The dividing wall ( 12 ) forms a capillary between the chip and the housing, the capillary action of which draws in the sealing material and the end of which stops the sealing material.

What is claimed is:  
     
       1. A sensor for detecting substances in a gas, comprising a substrate, 
       a semiconductor chip arranged on said substrate,  
       a housing for protecting the semiconductor chip, said housing comprising a top wall, side walls extending transversely to the top wall and a barrier section extending as a partition wall between opposite side walls, wherein the barrier section extends towards the semiconductor chip and divides the semiconductor chip into at least a first and a second part, wherein the first part is connected with the outside through at least one opening in the housing,  
       a measuring section arranged on the first part of the semiconductor chip and connected with an outside through said at least one opening,  
       bond wires connecting said semiconductor chip to said substrate, and  
       a hardened sealing material covering the second part at least partially, wherein said barrier section forms a barrier for the sealing material.  
     
     
       2. The sensor of  claim 1  wherein the barrier section approaches the semiconductor chip up to a gap and wherein the gap is filled by the sealing material. 
     
     
       3. The sensor of  claim 1  wherein the sealing material covers at least a part of the substrate. 
     
     
       4. The sensor of  claim 3  wherein the scaling material connects the substrate to the housing. 
     
     
       5. The sensor of  claim 3  wherein the scaling material covers bond wires between semiconductor chip and the substrate. 
     
     
       6. The sensor of  claim 1  wherein the side walls are resting on a margin section of the substrate and at least a part of the barrier section is set back compared to the side walls for providing space for the semiconductor chip. 
     
     
       7. The sensor of  claim 1  wherein the housing is a single part. 
     
     
       8. The sensor of  claim 1  wherein the housing is of plastics and is coated by a conductive layer. 
     
     
       9. The sensor of  claim 1  wherein the housing comprises a filling opening for the sealing material. 
     
     
       10. The sensor of  claim 1  wherein the housing extends around outer edges of the semiconductor chip. 
     
     
       11. A method for producing a sensor wherein the sensor comprises a semiconductor chip having a measuring section and being protected by a housing, said method comprising the steps of 
       arranging the semiconductor chip on a substrate and connecting the semiconductor chip with bond wires to the substrate,  
       placing a housing over the semiconductor chip, wherein said housing comprises a top wall, side walls extending transversely to the top wall and a barrier section formed by a partitioning wall between opposite side walls, wherein the barrier section extends towards the semiconductor chip and divides the semiconductor chip into a first and a second part, wherein the first part is connected through an opening in the housing to an outside and carries the measuring section,  
       covering the second part at least partially by a hardening sealing material while using said barrier section for preventing the sealing material from flowing into the first part.  
     
     
       12. The method of  claim 11  wherein the hardening sealing material is brought into a gap between the barrier section and the semiconductor chip by means of capillary forces. 
     
     
       13. The method of  claim 11  wherein several semiconductor chips are arranged on a substrate matrix and that a housing matrix of several, interconnected housings is brought onto the semiconductor chips, wherein in the area of each sensor sealing material is introduced, and wherein the substrate matrix is cut up together with the housing matrix for forming the individual sensors. 
     
     
       14. The method of  claim 13  characterized in that the sensors are brought into a reference environment and calibrated before being cut up. 
     
     
       15. The sensor of  claim 1  wherein an integrated circuit is arranged on the semiconductor chip. 
     
     
       16. The sensor of  claim 1  wherein the housing is of conducting plastics.